1998 starts then stalls 2-3 seconds

It is a 4.3L W type have replaced fuel pump, got 62 psi during prime cycle drops to 55psi for 1/2 hour that I was watching. I also replace CPI module, did a complete tune up Plugs, wires, rotor and d-cap. Replaced fuel filter, crank sensor. Tried new ignition module all with no change. The Jimmy starts then stalls almost immediately. Tried new battery also. Any suggestions on what to do next-----no codes show up either.

It is a 4.3L W type have replaced fuel pump, got 62 psi during prime cycle drops to 55psi for 1/2 hour that I was watching. I also replace CPI module, did a complete tune up Plugs, wires, rotor and d-cap. Replaced fuel filter, crank sensor. Tried new ignition module all with no change. The Jimmy starts then stalls almost immediately. Tried new battery also. Any suggestions on what to do next-----no codes show up either.

Your anti-theft /security system is shutting down.
Any after market remote start or anti theft stuff?
Key on.
Does the security light come on for a bulb check and go off?
If it stays on try a relearn on the system.
If relearn does not start it.
You will need to get it on a biody computer capable scanner and get body codes.
If any body codes post back code no.

Had a remote start, removed it thought it was the problem. I checked the yellow and orange/black wires from the ignition switch no spices or resistors soldered in. Security light goes out upon trying to start and does not come back on. I guess will have to find a body code scanner somewhere all I have is an OBD11 scanner.

Had a remote start, removed it thought it was the problem. I checked the yellow and orange/black wires from the ignition switch no spices or resistors soldered in. Security light goes out upon trying to start and does not come back on. I guess will have to find a body code scanner somewhere all I have is an OBD11 scanner.

Does the light stay on key on?
If a passlock system.
Try the relearn.
You will need a charger on batter when doing it.
Key on for 10 minutes and when secuirty light goes out.
Key off and back on 10 minutes.
Do it 3 times.
Then when light goes out on no 3 time turn off and wait a couple minutes and the start it.
Good luck

Security light goes off shortly (5 sec) after trying to start. Does the relearn still work if light not on ?

Does the light stay on after key on?

Try the relearn either way.
Let us know how it goes.

Light does not stay on. I will try the relearn, on- bump the starter leave on for 11 min turn off for a total of 3 times.

I was able to borrow a body code scanner from my friend that owns a garage near me. It came up with no codes present right now but had a code in the history p2951 which said it was an ignition switch fault. I cleared that code tried to start with the same result start then stall couple seconds later. Oh and rescanned no codes came back.

Light does not stay on. I will try the relearn, on- bump the starter leave on for 11 min turn off for a total of 3 times.

I was able to borrow a body code scanner from my friend that owns a garage near me. It came up with no codes present right now but had a code in the history p2951 which said it was an ignition switch fault. I cleared that code tried to start with the same result start then stall couple seconds later. Oh and rescanned no codes came back.

No on starter bump.
Light should stay on key on.
May have a problem there.
Do not bump starter on relearn.
Just key on for 10 minutes or more untill light goes out.
Then repeat 2 more times.

P code codes are engine codes.
Body codes are B codes or U codes.

Sorry that was a B2951, so used to the p codes. The security light doesn't stay on it goes out a couple seconds after the switch is turned on position

Light does not stay on key on, goes off after a couple seconds. Anyway the relearn did not do anything different still stalls. You alluded that the security light should stay on with key on which it does not.

Let me correct myself again it was B2961 code--- Key in ignition curcuit malfunction

Let me correct myself again it was B2961 code--- Key in ignition curcuit malfunction

No problem.
I have to correct the reprogram procedure to.
You were right on starter bump.

First step is key on with no starter bump then key on and bump starter.
After starte rbump security light should stay on.
Leave key on for 10 minutes or more untill security light goes out.
then key off and back on and bump starter and leave key on 10 minutes untill light goes out.
Repeat one more time or a total of 3 times.
Then key off .
Next key on it should start if it has relearned and no other problems.

code B2961 is a key in ign problem or mismatch.
If you have another good key try in to.
Did the sanner you have show key in ign data.
Good Luck And
Let us know how it goes.

The relearn procedure did not work, the security light goes out after a couple seconds does not stay on. The code I got B2961 was in the history not an active code. I was able to clear it so there are no active fault codes in the BCM. I'm still puzzled why the relearn doesn't work. I may have to see if I can borrow the scanner again to see if there is any key in ignition data as you mentioned.

Upon doing some research this morning the passlock sytem can be bypassed by placing the proper value resistor in the circuit. This may be my only option since the relearn procedure not working. I may try this when I get home later today if no other advice is recieved. I know the only bad thing I saw from the bypass is the BCM always thinks the right key is in the ignition. Also since I don't have the original key when the system was new and don't have the special passcode troubleshooting tool don't have many options available.

Upon doing some research this morning the passlock sytem can be bypassed by placing the proper value resistor in the circuit. This may be my only option since the relearn procedure not working. I may try this when I get home later today if no other advice is recieved. I know the only bad thing I saw from the bypass is the BCM always thinks the right key is in the ignition. Also since I don't have the original key when the system was new and don't have the special passcode troubleshooting tool don't have many options available.

We feel you pain on it.
Run a search on here on the bypass.
Good luck and let us know how it goes.

Well, attempted the bypass but felt the resistance value was way out 2.75 Meg and this was polarity specific because the other way read 0 ohms , my connection was the yellow lead going to the keyswitch to the insulation scraped off orange/black lead.:disappoin. So I put everything the way it's supposed to be and of course no difference. I did however get the security light to flash off and on but that went away after about 10 minutes and yellow wire reconnected.

Fix was the lock cylinder, being a rookie car repairman used a parts store replacement. A big NO-NO, when I did my resistance check the other night it dawned on me that that may well be the problem. I went and bought a new cylinder from GM dealer, had it set up at locksmith, installed and the vrooooom, worked as advertised.

Oh forgot to say thanks for all your help, even though I'm the cause of my own nightmare.

Oh forgot to say thanks for all your help, even though I'm the cause of my own nightmare.

You are welcome and thanks for posting back the fix and how it went.
Glad you found the problem and got it going.
And Yes GM oem parts only hurt one time.
Some after market stuff can bit in the rear many times.
Good Luck